BOMB protocol #6.7 TNA extraction from environmental samples

Nice to meet you. I am a university student in Japan. I am very struggling to extract and purify the DNA from soil. My professor is so old thinker and would like to make individual method, moreover it is cheaper. However, this is fool thinking and he does not absolutely buy general using kits. Therefore, I am struggling now. So I have a question to you. As you can see the subject, could this Magnetic Beads method apply the extraction and purification from soil?
Now, my using method is written below.

1. stainless steel beads 0.5 g, sample soil 0.5 g, extraction solution 1 mL, 20% SDS 0.2 mL, shaking tubes contain and shake in about 4000 rpm, 5 min.
2. after that, centrifuge in 15000 rpm, and transfer the supernatant 600 µL to micro tube and add the chloroform/isoamilalcohol same amount, resuspend and centrifuge.
3. transfer supernatant to new tube and add the 2-propanol, then centrifuge.
4. decant the supernatant and wash in 70% ethanol.
5. in the end, dry and resolve in TE solution or distilled milliQ water.

1-5 is extraction DNA way, but sample DNA solution contains much humus and so on. So, these are not clear and mainly colored blown or like black. therefore I make mistake and cannot apply PCR and Real-time PCR. purification method is gel cutting. But that is not efficient and lack of precision. Please help me.

I could not find the “soil” character but “environmental” exists. So could you apply this method to extract and purify the DNA from soil? I asked. Thank you in advance.

I am looking forward to hearing from you.